Jim Kelley wrote:
There is no convention describing
unidirectional flow of alternating current. That is what you've been
trying to say, i.e. current into one end of a coil.

When the instantaneous voltage across a resistor is '+' on one end
and '-' on the other, instantaneous current is flowing into the '+'
end and out the '-' end, by convention. What do you mean there is no
convention describing instantaneous current flow for AC? How could
we possibly be in the 21st Century without such a convention?

From _University_Physics_ by Young and Freedman, 9th edition:

"i = I cos(wt) where 'i' is the instantaneous current ..."

"But if we pass a sinusoidal current through a d'Arsonval
meter, the torque on the moving coil varies sinusoidally, WITH
ONE DIRECTION HALF THE TIME AND THE *OPPOSITE* DIRECTION THE
OTHER HALF." (emphasis mine so you won't miss it)

Instantaneous AC current "is represented by the projection (of a
phasor) onto a horizontal axis ...". A '+' sign for the cos(wt)
term represents one direction and a '-' sign represents the
opposite direction.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----